import java.math.BigDecimal;

public class Text {
    public static void main(String[] args) {
        double data1 = 0.1;
        double data2 = 0.3;

        BigDecimal b1 = BigDecimal.valueOf(data1);
        BigDecimal b2 = BigDecimal.valueOf(data2);

        BigDecimal c = b1.add (b2);
        double a = c.doubleValue();
        System.out.println(a);
    }
}
